The present invention relates to a unit for forming and supplying stacks of products to a machine.
In particular, the present invention relates to a unit of the above type for supplying stacks of products to a "form, fill and seal" packing machine.
The present invention may be used to advantage in the food conditioning industry, to which the following description refers purely by way of example.
In the food conditioning industry, stacks of products are formed, each comprising at least two superimposed products contacting each other, and each stack is fed to a "form, fill and seal" machine, for producing multiple packages of products, each defined by a given number of side by side stacks and enclosed in a single overwrapping.
Some known units for forming and supplying stacks of products comprise a continuous input conveyor for feeding a succession of products in a supply direction and on a bottom conveying surface to the input of a stacking device, which transfers the products continuously to its own output at a top surface so as to form, on the top surface, a succession of stacks of products; and an unloading device moving back and forth in an unloading direction through the output of the stacking device to successively remove and feed the stacks of products along the top surface to a machine.
Known units of the above type have proved unsuitable for use on production lines comprising high-speed packing and conditioning machines, on account of the downtime caused by the back and forth movement of the unloading device through the output of the stacking device, and which is unacceptable on modern production lines.
To overcome the above drawback, the unloading device has been replaced by a pocket conveyor traveling in steps in the unloading direction through the output of the stacking device. More specifically, each pocket on the conveyor is designed to contain a respective stack of products; is arrested at the output of the stacking device before the products eventually forming the stack associated with the pocket are fed to the output; and, after receiving the respective stack of products from the stacking device, is fed in steps in the unloading direction to feed the stack to the machine.
While indeed succeeding in reducing, in fact substantially halving, the downtime involved previously, the above pocket conveyor still involves a certain amount of downtime due to stacking of the products having to be suspended as the conveyor is moved forward and until the next empty pocket is arrested at the output of the stacking device.